How deep is your love
Divernet
How deep would you dive to save someone close to you The heart might rule the head in an emergency, and narcosis affect your judgment anyway, but attempts to answer the question are clouded by confusion about the dangers of deep-diving on air, says Mark Bauwens

SOME OF US DIVE WITH A VARIETY OF OTHER PEOPLE, some with regular buddies. Perhaps you have considered how far you would go to rescue your buddy in an emergency. Suppose he or she was in trouble at depth - how deep could you dive safely to fetch them back What depth would be suicidal Or would you dive to any depth, regardless
ÂÂÂÂ Such sobering questions become even more acute in the case of permanent partners who dive together, and have more than a simple duty of care to one another. Would they discuss the issue together and come up with a plan And could they keep to that plan despite the narcotic effects of nitrogen
ÂÂÂÂ When I put these questions to 50 random diving couples at this years London International Dive Show, it turned out that only 6 per cent had ever considered the matter. The usual response of the vast majority to the question: How deep would you dive to save your partner was along the lines of: Whatever it took. Some said: Lifes too short to worry about it.
ÂÂÂÂ Four per cent said they would not attempt a rescue. When their partner looked understandably hurt, unsurprisingly they relented. Some joked that they wouldnt bother, others mentioned the insurance.
ÂÂÂÂ Only 2 per cent said they had a mutual rescue plan, based on the maximum depth for which they had been certified.
ÂÂÂÂ What about rescuing unknown divers Sixty per cent of all those interviewed said they wouldnt rescue me. But when I asked if they thought they might change their mind at depth, with a diver needing assistance beneath them, most accepted that they would, if there was no one else about.
ÂÂÂÂ Dependants add another dimension to the question. One couple with three children said the subject had not come up before but that they would go home, discuss it and agree a plan. After all, as much as the parents might love one another, they also wanted to be sure that the children would go on being looked after by at least one of them.
ÂÂÂÂ It seems clear from the responses that we prefer to put to the backs of our minds unpalatable subjects such as injury, death, being left without a partner or our children being orphaned. Diving is, after all, supposed to be fun, entertaining and safe.


ÂÂÂÂ What struck me, however, was that so few of the people to whom I spoke seemed aware of the consequences of deep-diving on air. Comparatively few, it appeared, remembered their training.
ÂÂÂÂ Some divers mentioned the problems posed by limited air supply at depth, but not a single one pointed out that judgment under water could not be relied on because of nitrogen narcosis and that, therefore, any rescue attempt decided on at depth would be potentially flawed.
ÂÂÂÂ And there was in any case confusion about what it was that made diving deep on air dangerous. Was it nitrogen narcosis or oxygen toxicity Did dive time, individual diver physiology on the day or workload play a significant part
ÂÂÂÂ And if you ever had to make a deep emergency dive, perhaps beyond your normal range of experience, would you be able to handle it
ÂÂÂÂ I later sought the views of expert divers and asked them how deep they would dive on air to save their partners - or anyone else, for that matter. They included the men who run PADI and technical diving training agencies the IANTD and TDI in Britain, as well as a Health & Safety Executive expert. As far as the central question was concerned, I was interested in their personal views rather than any official position.
ÂÂÂÂ In the past I wouldnt go to more than 60m on air and that has to be under pretty good conditions, says Mark Caney, one of the directors of PADI International, who dives with his partner Angela. Its too extreme beyond that.


src=http://diverfiles.net-genie.co.uk/data/images/0701risk5.jpg If Angela were to disappear into the depths unexpectedly then, yes, I would follow her, says Mark Caney. I made a point of putting her through the Rescue Diver course and that very much focused her mind on the possibility

ÂÂÂÂ Caney is a PADI Instructor Examiner and also has ANDI Trimix Instructor and BSAC National Instructor qualifications. In an emergency situation I might go somewhat deeper, but not very much. Even 60m I dont tend to do these days, because Im not diving as regularly as I did.
ÂÂÂÂ But if Angela were to disappear into the depths unexpectedly then, yes, I would follow her, he says. I made a point of putting her through the Rescue Diver course and that very much focused her mind on the possibility. I suppose, like most divers, I dont anticipate myself getting into trouble. You always assume it wont be you!
ÂÂÂÂ Caney has a safety plan, though he describes it as extremely flexible.
ÂÂÂÂ I would never compromise safety, but Ive done the whole range from simple little introductory dives through to trimix 100m-plus dives, and theres a tremendous difference in the amount of planning and safety precautions you need to take, according to the environment and the conditions.
ÂÂÂÂ Dave Crockford trains TDI closed-circuit rebreather instructors and is also a BSAC National Instructor. He and his wife Alison own the UK TDI franchise, though Alison doesnt dive. Ive got two very gorgeous daughters and theyve been my life and I want to be there for them when Im old and grey, says Crockford.


ÂÂÂÂ I plan all my dives and Im very strict about what depth I go to and what time I spend at that depth. Thirty-five metres feels right for me on air, my personal narcosis level. He says that this level has changed over the years. Its become shallower year by year and hovers between 25-35m, though its now three or four years since I dived on air.
ÂÂÂÂ On air I would absolutely not dive deeper than 35m to rescue someone, he says, though then concedes that he could envisage circumstances that might override that policy. If it were one of the girls, in a few years time, in an emotional situation, then at depth narcosis would cause me to change that plan.


src=http://diverfiles.net-genie.co.uk/data/images/0701risk4.jpg Ive got two kids, so if Im putting myself in danger by rescuing my wife, already in danger, Im not going to do that, because then my kids have no parents at all, says Kevin Gurr

ÂÂÂÂ IANTD Instructor Trainer Kevin Gurr is perhaps best known as a trimix expedition leader. The bottom line for rescuing a family member is that you will possibly extend your plan a little bit, but try still to work within a safe environment. Ive got two kids, so if Im putting myself in danger by rescuing my wife, already in danger, Im not going to do that, because then my kids have no parents at all.
ÂÂÂÂ Gurrs wife Mandy co-owns the UK IANTD franchise. Thats a nasty question! she says, but her response is similar. I couldnt do it, weve got children. I think Kevin would be very cross with me if I did do something like that.
ÂÂÂÂ But its a very emotional thing to ask. You see someone you love, it would be very difficult not to try to help him.
ÂÂÂÂ Kevin Gurr points out that its difficult in any case to formulate a single safety plan. Every rescue is unique and its not really depth-dependent as such, because the limits change depending on gas supply, dive time... You will attempt to rescue that person to the best of your ability until you feel its too damn dangerous and youre going to get injured as well.
ÂÂÂÂ Some of the training that occurred 10 to15 years ago was better - now you can qualify too quickly as a diver. Some of the stress-management training not to panic, and exposure to minor incidents, which you deal with and survive under training, is being missed out. Good survival skills need to be taught.

src=http://diverfiles.net-genie.co.uk/data/images/0701risk2.jpg Im not sure whether my need to save my wife would overtake my commonsense, experience and training, says Mike Harwood. Its a fact that the deeper you go, the less reliable your judgment becomes

ÂÂÂÂ Mike Harwood, the Health & Safety Executive inspector responsible for recreational and commercial diving in the UK, and a former military diver, was also asked to consider the question of how far he would go to save a loved one.
ÂÂÂÂ I dont believe I could actually say I wouldnt go deeper than about 50m, was his response. Im not sure whether my need to save my wife would overtake my common sense, experience and training. Its a fact that the deeper you go, the less reliable your judgment becomes.


ÂÂÂÂ Which brings us back to the question of how far we can assume it is reasonably safe to go in carrying out such a rescue, bearing in mind the twin perils of nitrogen narcosis and, at greater depths, oxygen toxicity.
ÂÂÂÂ When we put the HSE Approved Code of Practice through for recreational diving, we recognised that recreational divers would dive beyond 50m, says Harwood. The HSE has recommended 1.4 bar partial pressure of oxygen for scuba [equivalent to 56m] and 1.5 bar pp02 for surface supply with a full-face mask but a 50m enforced maximum depth for commercial divers. We dont have a maximum for nitrogen.
ÂÂÂÂ In fact maximum partial pressure of nitrogen levels are rarely expressed, even though most experts agree that it is nitrogens narcotic effect that causes more problems for recreational divers than oxygen toxicity.
ÂÂÂÂ But the latter is a factor for any diver descending beyond recreational limits on air (or shallower if using nitrox mixtures). As we learn in basic training, it is the partial pressure of a gas that determines the amount of that gas that dissolves into our bloodstreams. Air is 21 per cent oxygen and as such exerts about a fifth of the total pressure, or 0.21 bar at the surface. By the time you reach 50m that partial pressure (pp02), is nearing 1.3 bar.


ÂÂÂÂ In terms of pp02, maximum depth limits for sport divers as laid down by the various training agencies vary between 1.3 and 1.6 bar. The conservative1.3 bar limit implies that it is potentially dangerous to descend beyond 52m, while the more generous 1.6 bar gives a threshold of 66m. Thats a 14m gap between the figures.
ÂÂÂÂ Oxygen, if breathed at a partial pressure greater than - well, take your pick, 1.3 or 1.6 bar - can be poisonous to the body, usually affecting our brain tissues. Its onset can be sudden and the results are unconsciousness or seizures. You might get a hit at depth, you might not. Its a matter of Russian roulette, and not all the factors are fully understood.
ÂÂÂÂ It would seem bizarre if motorists belonging to the AA were certified to drive on the M1 at 80mph, while members of the RAC could drive at 85mph and Green Flag members at 90mph. So how come the UKs competing diver-certifying agencies have different maximum dive depths on air, expressed as maximum pp02 Are the higher levels wrong
ÂÂÂÂ We didnt want to be hard-nosed and say no, you cant do that, but divers have to understand the risks, says Harwood. Its their personal choice. Each agency has taken its own steps to control the depths of the qualification that people go to.
ÂÂÂÂ Some divers decide to do something which is deeper than that. Thats their choice, and I dont believe you can ask agencies to control what the public decides to do once they have their qualification. If you want to take the risk...


ÂÂÂÂ In the USA, Hal Watts Professional Scuba Association runs a deep-air course to 73m (and Level VII to 91m), though the IANTD and TDI have withdrawn their deep-air courses. We are aware of what Hal Watts is doing, says Mike Harwood. We would not sanction that sort of diving in this country. If thats the choice of UK divers, thats fine, so long as they understand the risks theyre taking.

src=http://diverfiles.net-genie.co.uk/data/images/0701risk3.jpg Ive got two very gorgeous daughters and theyve been my life and I want to be there for them when Im old and grey, says Dave Crockford

ÂÂÂÂ In the 1970s divers learnt using Royal Navy tables, which went to 70/75m, and dived beyond that. Peer pressure has changed somewhat, says Dave Crockford. Instructors now understand that they have a duty of care to the individual. Its much stronger than it was when we used to dive by osmosis.
ÂÂÂÂ In those days, he says, anything you can do I can do better was the rule. Now the HSE is starting to get the bull by the horns and wake the instructors and agencies up to the fact that they do have a very strong duty of care.
ÂÂÂÂ If I had the level of understanding 20 years ago that I have now, I would not have entertained half of what I did. I think one of the greatest dangers at depth remains bravado.
ÂÂÂÂ The tables did go to 70/75m but I dont think its safe for anyone to dive to 75m on air, says Mark Caney. I also think depth is not the only factor.
ÂÂÂÂ A real danger, a real killer, is narcosis. Its the big hazard once youre getting below 50m. Its such a subtle thing that many people have fallen foul of it, especially experienced divers in places such as the Red Sea.
 Theyll go to 40m and think: ÔIm fine here, Im not really affected, and then try 50m, then 60m and before you know it theyre going down to 100m!
ÂÂÂÂ That will work some of the time but, sooner or later, youll get a narcosis hit and theres no warning for that!
ÂÂÂÂ Divers are not always affected by narcosis at the same depth, says Caney. I think there are variations according to the day, your health situation, how frequently youre diving and other factors. And unfamiliar conditions can lead to problems. I have certainly seen the inverse of popular wisdom, which is that if you learn to dive in the UK, you can handle anything. Theres a tremendous difference between diving to 40m in Dorothea Quarry and to a similar depth in the Red Sea.
ÂÂÂÂ People who have dived a lot in poor conditions go somewhere like the Red Sea and, because the waters so clear, find themselves at 60-70m without realising it. They dont associate that clarity of water with depth.
ÂÂÂÂ We always make sure we train where there is a hard bottom, says Kevin Gurr. Its part of the risk assessment.


ÂÂÂÂ So should all divers in unfamiliar surroundings limit themselves to dive sites with a bottom at a safe depth You need to be very disciplined to dive a site which has no fixed bottom, says Caney. British divers are generally considered very good divers internationally, but they dont necessarily have the best reputation for buoyancy control.
ÂÂÂÂ They think: Ill just go to the bottom and sort myself out there. Thats all very well at a fixed depth, but if youre off the wall in Ras Mohammed, you cant really do that!
ÂÂÂÂ Caney says he feels PADI was largely responsible for doing away with the mentality that all divers had to dive deep and must do decompression dives. We have always had a philosophy that 30m was plenty for most divers, 40m was the absolute maximum.
ÂÂÂÂ That was quite a dramatic change in attitude to the traditional European agencies, which always associated depth and decompression with experience - in fact, it was usually required.
ÂÂÂÂ As a result, divers came away from their courses with attitudes that they must dive deep, must do decompression dives. We have probably reduced the number of accidents significantly.


ÂÂÂÂ Was there not a danger, then, that divers would view with some cynicism PADIs TecRec deep-air diver course to 50m with staged decompression, when it is rolled out this summer
ÂÂÂÂ When people look at what you have to do to be able to go to 50m, I think theyll see the difference, says Caney. The course is extremely rigorous. The requirements to attend the course are very high and the amount of additional equipment, planning and additional techniques involved to be able to go those extra 10m are substantial. Its a very different kind of diving.
ÂÂÂÂ Whichever depth is the law for your certification agency, some divers will exceed it, just as some motorists break the law. Would a joint combined industry approach to depths on air, expressed as pp02 or ppN2, help divers understand the risks better
ÂÂÂÂ The agencies do get together in some respects, but something like gas laws and how human beings react to different gases is a dynamic art, says Mark Caney. Its something were learning about the whole time, and in the time Ive been diving Ive seen limits change and generally become more conservative. In a way its happened without the agencies getting together. The maximum depths they recommend are not very different.
ÂÂÂÂ Recommended maximum depths have fallen by around a third in the past 30 years. I think to a large degree analysis of accidents has been the driving force, says Caney. Using air to 75m youll get pretty regular accidents.
ÂÂÂÂ Were starting to get more and more dialogue between industry professionals and agency professionals, says Dave Crockford. Whats happened is that, way back, the industry thought 2 bar max ppO2 [equivalent to 85m] was appropriate, then came to 1.6 bar.
ÂÂÂÂ I believe the majority of the recreational industry has settled on 1.4 bar, especially for European waters. It would be nice to think that on a worldwide approach it will become 1.4 bar or even 1.3 bar max ppO2.
ÂÂÂÂ Though DAN in the USA has just stated 1.6 bar as a new maximum, he says it could not apply that limit in areas such as the UK and parts of Europe which have cold water.
ÂÂÂÂ Ive a feeling that we do need to work right across the board and get one standard. 1.4 bar seems right for us. I feel it would be right for the world. And nitrogen The equivalent for 35m depth on air, about 3.5 bar ppN2 maximum.


ÂÂÂÂ To what extent was the reduction in recommended safe levels connected with the diving agencies now being held accountable, and legislating for the least able and fit Not much, I suspect, says Mark Caney. When the BSAC reduced the limit to 50m, I dont think it was particularly concerned with commercial pressures and liability issues at the time. It was a straightforward safety decision.
ÂÂÂÂ Certainly for PADI it was pretty much a question of looking at the data and 40m was a logical conclusion, using recreational diving techniques and equipment. 40m was plenty for even experienced divers.
ÂÂÂÂ We all used to drive cars without seatbelts. I heard on the radio the other day that theres a bit of a crisis in this country because of a shortage of organ-donors. One of the reasons was that the introduction of seatbelts had reduced the number of injuries and the number of organs available. Likewise, in diving, if we were still putting divers into the water and letting them all go to 75m on air, wed have a lot more deaths.
ÂÂÂÂ The main thing is to make sure youre trained for the dive youre doing, that youre in practice and you have a plan in your mind of what to do if things go wrong.
ÂÂÂÂ Air is fine for walking around in and breathing, but for taking under water its not really a smart move, is the view of Kevin Gurr. Most people set the narcotic depth of trimix at between 30-40m equivalent air depth, which is a pretty smart move.
ÂÂÂÂ The deeper I go, the shallower I put my narcotic depth. On a 120m dive on trimix Im on a gas thats equal to 30m on air. I want to feel as if Im on the damn surface when things go wrong.


ÂÂÂÂ So would 30m be an acceptable limit on air, given that tolerance to nitrogen builds only over time Remember, its not a physiological tolerance. Your body is not adapting, its your mind adapting. Slowly your technique adapts. You move slower, you feel better. If you stress someone at 30m, which is relatively shallow, you can produce severe amounts of narcosis. So if youre saying, is there a safe narcotic depth, I dont think you can make it that fine a line.
ÂÂÂÂ And there is always that problem of oxygen toxicity at depth. Ive seen a person dive for three minutes on 100 per cent oxygen at 42m or 5.2 bar ppO2 pressure before they convulsed. Oxygen toxicity is always time-dependent, pressure-related and personal-tolerance dependent on the day. I might not convulse today at 1.6 bar, but I might do tomorrow.
ÂÂÂÂ My own wife is dive-fit, healthy and used to diving with me to a maximum 65m on air - thats in warmer seas with better visibility than in the UK and at the end of a work-up programme. But I have told her she must never try to rescue me beyond 70m on air.
ÂÂÂÂ She understands that, at more than 1.6 bar ppO2, she would not have much time at that depth. Also, at nearly 6.5 bar ppN2, she would be very high and, in an emergency in which she would be emotional and breathing hard, would be at great risk, yet probably oblivious to it.
ÂÂÂÂ Her relaxed air consumption would be around 200 litres/min at 70m, so a typical holiday cylinder would last only 10 minutes if two-thirds full, and at a 10m/min ascent rate it would take her 11 minutes to surface without a deco stop but with a minimum safety stop.
ÂÂÂÂ She has promised me that after, say, 15 minutes of starting a dive she would not attempt to rescue me from 70m, as it would not be survivable.
ÂÂÂÂ There would not be sufficient air for her, let alone me, assuming I had run out. But if it came to the crunch, would she do as she was told And would your own partner - or would love and narcosis take over


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